Could Snails Help Humans Regrow Their Eyes? Here's What Science Says

The ability to regenerate lost body parts has long captured human fascination. Many creatures out in nature can perform feats of repair that far surpass our own abilities. For example, salamanders can regrow limbs, starfish can replace their arms, and lobsters can regrow their limbs, claws, and even antennae. However, for humans, this level of regeneration remains firmly out of reach, especially when it comes to sensitive organs such as the eyes.

That said, scientists started turning their attention to a more unexpected model: snails. A new study published in Nature Communications shows that the apple snail can completely regrow its camera-type eyes after full removal. The findings don't imply that human eye regeneration is imminent, but they open a fresh line of investigation into how complex organs could be regenerated. By studying what other creatures can already achieve, researchers hope to uncover breakthroughs in human medicine and turn organ regeneration into reality.

The new study, headed by Alice Accorsi of the Stowers Institute for Medical Research, focuses on the apple snail, Pomacea canaliculata, a freshwater mollusk with a surprisingly sophisticated visual system. These snails possess what are known as camera-type eyes. These visual organs, like human eyes, use a cornea and lens to focus light into a layered retina, where photoreceptors convert light into a signal to the brain. This is what makes apple snails fundamentally different from other invertebrates with simple eyespots. In fact, their eyes are more comparable to the eyes of vertebrates, including our own.

Researchers completely removed the eye of the apple snail to test its regenerative abilities. They even removed the stalk on which the eye sits. Remarkably, it took these snails only one month to fully regrow the organ. And the process wasn't limited to regrowing only the surface tissue. Every major component of the eye was rebuilt, including the optic nerve. Scientists were able to fully follow the regeneration process. It started with wound closure, proliferation of new cells, and formation of blastema (a cluster of cells that acts as a regeneration hub). Only then does the gradual differentiation into the complex layers of the eye begin.

More importantly, the research team investigated the genetic mechanisms that drove the eye's recovery. They managed to zero in on a master gene, pax6, that is long recognized as the essential gene for eye growth in various animal species on Earth. Once the scientists disabled pax6, the apple snails lost the ability to regenerate their eyes.

The discovery made by the scientists at Stowers Institute for Medical Research positions apple snails as a new model organism for regrowth research. These snails are easy to keep and study, and they have complex eyes that can be fully rebuilt. They're the perfect test subjects for future research that may push current medical frontiers. For humans, eye damage is often permanent. While the human cornea can heal itself to some degree, injuries to the retina or damage to the optic nerve have limited options for repair. Current treatments can restore some functions of the eye and improve vision to a degree, but they cannot rebuild the eye fully. The idea that humans could regrow complex organs, such as eyes, poses many challenges.

The apple snail study shows that the eye can be fully regrown. For humans, it won't happen overnight, but it helps us understand the rules of regeneration in nature. One day, this may lead to the full or partial reconstruction of the human lens, retina, optic nerve, and the supporting eye tissue. If researchers can find which molecular pathways are active in snails but remain silent in humans, it could lead us to new strategies for unlocking humans' capacity for self-repair.

Still, major hurdles remain. Snails and humans are evolutionarily very distant relatives. What works in one species may not directly translate to the other. However, snails do help us understand the extraordinary regenerative abilities many animals already possess. New potentials of regenerative medicine are being intensely explored. Even if humans never manage to fully regrow their eyes, these snails can help with future eye degeneration therapies and even enhance the success of transplants. Who knows, maybe an apple snail a day will keep the doctor away.